Leica MX421 Series User manual

l
MX421
High Precision GPS Sensor
Installation
Manual

MX421
High Precision GPS Sensor
INSTALLATION MANUAL
Models Covered:
MX421
MX421B
MX421-10
MX421B-10
MX421SB-10
Leica Geosystems Inc.
23868HawthorneBlvd.
Torrance,CA 90505-5908
U.S.A.
www.leica-geosystems.com
P/N723594
Rev. C
August,2001

Leica Geosystems Inc. 2001
Leica Geosystems reserves the right to make changes to its products and
specifications without notice.

How To Contact Us?
Contact your local Leica dealer for:
•Installation, Service, & Technical Support
•Sales of Accessories
•Hardware and Software Upgrades
Unlikemany other consumerelectronics industries whichonly sell consumerelec-
tronic devices, your marine dealer is often your best advisor for installation and
service of your new GPS receiver. Leica strongly encourages you to utilize the
knowledge and experience of your sales and service dealer.
Should you need to contact us directly for new sales, upgrades, repair service, or
technical support, we can be reached at the following:
International:
Leica Geosystems Inc.
23868 Hawthorne Blvd.
Torrance, California 90505
USA+1-310-791-5300 Telephone (International)
1-800-97-LEICA (1-800-975-3422) Telephone (USA)
[phone] Fax
[email protected]
In Europe:Leica Geosystems A/S
Høkær12A
DK-2730 Herlev
Denmark
[phone] Telephone
[phone] Fax

TableofContents
Introduction ....................................................................................................... 1
MX421 Operation............................................................................................... 2
Antenna Connector...................................................................................... 3
Supplied Equipment ......................................................................................... 4
MX421 Mounting Guidelines ............................................................................ 6
Installation Procedure ...................................................................................... 6
Antenna Mounting ............................................................................................ 6
Bracket Mount .............................................................................................. 6
Surface Mount .............................................................................................. 6
Figure 2 - MX421 Bracket Mount ........................................................... 7
Figure 3 - MX421 Surface Mount ........................................................... 7
MX421 Installation Section............................................................................... 9
Power Requirement ................................................................................... 10
MX421 Connector Configuration .............................................................. 11
Figure 4 - Interface Cable Pin Configuration for MX421.................... 11
MX421B Connector Configuration............................................................ 12
Figure 5 - Interface Cable Configuration for MX421B....................... 12
Data Interface to MK40 Chartplotter......................................................... 13
Figure 6 - MX421 Interface to the MK40 Chartplotter......................... 13
Data Interface to PC or Non-Leica Navigation Systems........................ 14
Figure 7 - MX421 Interface to PC or other Non-Leica Navigation
Systems ................................................................................................. 14
PC Interface Cable ..................................................................................... 15
Figure 8 - MX421 to PC Interface Cable (P/N 722206) ....................... 15
MX421-10 Installation Section........................................................................ 17
Power Requirement ................................................................................... 18
MX421-10 Connector Configuration......................................................... 19
Figure 9 - Interface Cable Pin Configuration for
MX421-10 ............................................................................................... 19
External Differential Beacon Receiver Connection ................................ 19
MX421B-10 & MX421SB-10 Connector Configuration ............................ 20
Figure 10 - Interface Cable Configuration for MX421B-10 and
MX421SB-10 .......................................................................................... 20
Data Interface to MK40 Chartplotter......................................................... 21
Figure 11 - MX421-10 Interface to the MK40
Chartplotter ........................................................................................... 21

Data Interface to MX420/2 or MK12 CDU.................................................. 22
Figure 12 - MX421-10 Interface to a MX420/2 and MK12 CDUs........ 22
Data Interface to MX420/8 or MX420/AIS CDU......................................... 23
Figure 13 - MX421-10 Interface to MX420/8 or MX420/AIS CDUs...... 23
Data Interface to PC or Non-Leica Navigation Systems........................ 24
Figure 14 - MX421-10 Interface to a PC chartplotter or Other Non-
Leica Navigation Systems.................................................................... 24
Specifications.................................................................................................. 25
Data Output ..................................................................................................... 27
PRODUCT WARRANTY AND LIMITATION OF LIABILITY............................. 30
How Are We Doing? ........................................................................................ 32

1
MX421 Installation Manual
Introduction
This manual describes the operation and installation of the MX421 family of high-
precision GPS smart antennas.
TheMX421 GPS andDGPS smart antennasweredesigned toworkwith the latest
LeicaControl and DisplayUnits (CDU)or other NMEA0183 compatible navigation
devices. TheMX421canachievepositionfixaccuraciesof better than 1 meter with
differential correction or better than 3 meters without correction.
Antennamodels covered inthis manual are:
MX421 - a GPS only smart antenna with an 8-pin power/data connector.
MX421B - a combined GPS and Differential beacon smart antenna with an 8-pin
power/dataconnector. The beaconreceiveroperates in automaticmode
only.
MX421-10 - a GPS only smart antenna with a 10-pin power/data connector. This
antenna can accept differential corrections from an external beacon re-
ceiver. A 1 PPS timing output is optionally available.
MX421B-10 - a combined GPS and Differential beacon smart antenna with a 10-
pin power/data connector. The built-in beacon receiver operates in auto
mode.
MX421SB-10 - an enhanced MX421B-10 with a controllable built-in differential
beacon receiver. The built-in differential beacon receiver can be oper-
ated in either auto or manual mode when connected to an MX420 CDU.
These models use identical housing styles. To determine the particular model of
antennayouhave,please check thenumberofconnectorpins and themodelnum-
ber inscribed on the serial number tag located at the underside of the antenna
housing and consult the section in this manual that refers to it.
Before installing the MX421, please read this manual carefully to ensure proper
installation and operation of the unit.

2
MX421 Installation Manual
MX421 Operation
The MX421 and MX421B sensors are highly integrated antenna and GPS re-
ceiver units that are fully automatic and do not require user intervention. They will
automatically search for available satellites as soon as power is applied. The in-
ternal 2-channel beacon receiver in the MX421B and MX421B-10 continuously
monitors all beacon signals available in your location. The first channel tracks the
primary station while the second channel searches for other available beacons.
Should it find a superior signal it will automatically switch the primary channel to
the new station. The combined performance of the high-precision 12-channel
GPS and 2-channel beacon receivers provide a more accurate and reliable posi-
tion fix, usually within 1 meter or less.
The MX421SB-10 is an enhanced MX421B-10 DGPS smart antenna unit that can
either automatically tune to the beacon frequency or can be controlled by a Leica
MX420CDU to manuallyselect thebeacon frequency.
The MX421 DGPS was designed with an H-Field beacon antenna for better on-
boardelectrical noise immunityand requires nogrounding.

3
MX421 Installation Manual
Antenna Connector
The multi-pin connector at the bottom of the antenna housing provides the neces-
sary interfacing between the MX421 smart antenna and the latest Leica CDU or
otherNMEAcompatibledevices. Older productionMX421antennasuse8-pincon-
nectors while new build units (MX421-10) use 10-pin connectors. The interface
connections from pins 1 through 6 are similar for all MX421 models. There are
slightdifferencesinPins7&10foreachmodel,whichareindicatedinTable1. The
twoadditional pins (9&10) onthenewer production MX421are used tooutput the
1 PPS signal.
Table 1 - MX421 Smart Antenna Configuration
8-Pin Conn. (old) 10-Pin Conn. (new)
Pin
#Wire Color MX421
GPS MX421B DGPS MX421-10 GPS MX421B-10 DGPS
1BLK/
SHIELD Negative Ground
2RED +10.5 ~ 32 VDC
3BLU Leica Proprietary Message (LPM) In (-)
4BRN Leica Proprietary Message (LPM) In (+)
5ORG GPS Out (-)
6GRN GPS Out (+)
7YEL N/C Beacon Status
Out (-) RTCM In (-) Beacon Status Out (-)
8WHT N/C Beacon Status
Out (+) RTCM In (+) Beacon Status Out (+)
9PRPL N/A N/A 1 PPS (+)
10 PRPL/
GRY N/A N/A 1 PPS (-)

4
MX421 Installation Manual
Supplied Equipment
The following items are supplied with the MX421 Sensor:
Description Part Number
(8-Pin Type)
MX421 723240
or,
MX421B 723241
Antenna Cable Assy. (10 m.)
(8-wire cable) 722569
MX421 Installation Manual 723594
(10-Pin Type)
MX421-10 726233
or,
MX421B-10 726232
or,
Antenna Cable Assy. (15 m.)725637
(10-wire cable)
MX421 Installation Manual 723594

5
MX421 Installation Manual
MX421 High Precision GPS Sensor
Installation
Manual
Figure 1 - MX421 Sensor Standard Package

6
MX421 Installation Manual
MX421 Mounting Guidelines
•Install the MX421 where it has a clear view of the sky around it.
•Locate the antenna for an easy access and maintenance.
•Stay away from high-power energy sources such as radar, SSB,
INMARSAT and other transmitting radio antennas by 5 meters or more.
•Locate the antenna at least 10 feet (about 3 meters) away from and out of
thetransmitting beam ofradarand otherhigh-powertransmitters.
•Mountthe antenna lowto avoidexcessive position andspeed errors while
underway.
Note: If you are not sure if the chosen location is appropriate, you can mount
the antenna temporarily and operate the unit. Monitor the operation of
theMX421 while you turnonother on-board electronicequipment. Move
the antenna around until the MX421 operates satisfactorily then mount
it permanently.
Installation Procedure
Antenna Mounting
Bracket Mount
TheMX421mountingthreadis an industry standardfittingforVHFantennamount-
ing(1.0 inch, 14TPI) . This enablesthe antenna tobemounted onawide range of
mounting brackets, including the swivel joints, commonly used for angled surface.
Refer to Fig. 2 for bracket mounting illustration.
Note: Hand-tighten the antenna onto the bracket until snug. Do not over-
tighten.
Surface Mount
The MX421 may also be surface-mounted.A template is provided to help you cut
themounting holes. There mustbe at leasta 3 inch clearanceatthe bottomofthe
antenna to accommodate the lower section of the MX421 housing and connector.
Referto Fig.3 forsurface mounting considerations.
An 8 or 10 pin (male) plastic connector is mounted at the underside of the antenna
forpower and dataconnection.
The supplied cable assembly is 10 meters (33 feet) long, with an 8 or 10-pin
(female)connectoron one end. Thisconnectorplugs into theMX421. Whenused

7
MX421 Installation Manual
with the MK40 chartplotter or MX420 CDU, the other end of the cable (with loose
wires) connects to the antenna junction box as shown in Figure 4. If the MX421 is
tobeusedwithothernavigation system, refer to Figure7(ConnectiontoNon-Leica
NavigationSystems).
Choosealocation for theantennathat has aclearview of thesky. Makesure there
are no major obstructions or metal fixtures in the immediate proximity to the an-
tenna. The GPS antenna relies on direct ‘line-of-sight’ signal reception. If you are
unsure that the chosen location is suitable, it is advisable to mount the antenna in
atemporary manner toverify correct operation.
Mounting
Surface
1” Diameter/14 TPI
Metal Mounting
Bracket
(not supplied)
Drill 1/4” diameter hole
for cable access
Secure cable
with plastic
tie-wraps
(not supplied)
Figure 2 - MX421 Bracket Mount
3
.
0
”
Mounting
screws (4 places)
Recommended
clearance under
the antenna
Mounting
Surface
Figure 3 - MX421 Surface Mount

8
MX421 Installation Manual

9
MX421 Installation Manual
MX421 Installation Section
(Use this section when installing the MX421 or the MX421B
with 8-pin connector)

10
MX421 Installation Manual
Power Requirement
External power supplied to the MX421 must be within 10.5-32 VDC for best
operation. To protect the circuitry in the antenna, the voltage level must be within
these limits. Negative grounding is required. The MX421B draws about 230 mA.
at 12 VDC. An in-line fuse or circuit breaker rated at 2 amp. is recommended for
overload protection.
When the MX421 is connected to a Leica control display unit (CDU), the antenna
power can be supplied by the CDU unit.
The red wire connects to the +12 VDC power, while the black wire is the negative
return. Althoughthe MX421 hasa reverse polarityprotection, it isprudentto make
surethat proper polarityis observed beforemaking the connection.
Note: Reverse polarity connection may damage the unit.

11
MX421 Installation Manual
MX421 Connector Configuration
The MX421 is a smart GPS only antenna configuration. It transmits the NMEA
data at 4800 baud, 8 bits, 1 stop, no parity. Figure 4 shows the MX421 connector
pin assignments.
82
3
4
5
6
71
Pin#WireSignal
8 White N/C
7 Yellow N/C
6 Green GPS Out +
5 Orange GPS Out -
4 Brown LPM IN+
3 Blue LPM IN-
2 Red +12 VDC
1 Black GND.
Figure 4 - Interface Cable Pin Configuration for MX421
Where:
Pins 1 & 2: are used for GND and 12 VDC input.
Pins 3 & 4: Leica proprietary message (LPM) input port.
Pins 5 & 6: GPS output to the MK40, MX420 (CDU) or other NMEA 183
compatible devices.
Pins 7 & 8: Not connected.

12
MX421 Installation Manual
MX421B Connector Configuration
The MX421B antenna configuration is a combination GPS and beacon receiver in
one.Thebuilt-indifferentialreceiveroperatesinauto-searchmode. Itenhancesthe
accuracyoftheGPSreceivertoprovideamoreaccuratepositionsolution. Position
accuracy better than 1 meter is possible with this configuration.
It transmits the NMEA data at 4800 bauds, 8 bits, 1 stop, no parity. Figure5 shows
thewiringand pin assignmentsforthe MX421B antenna. Theoutputon pins 5and
6canbe optionally set tooutputGGAat 5 Hz.ThestandardNMEA0183 protocol is
the factory default setting.
Data output change may be done only in the factory.
82
3
4
5
6
71
Pin#WireSignal
8 White Beacon OUT+
7 Yellow Beacon OUT-
6 Green GPS Out +
5 Orange GPS Out -
4 Brown LPM IN+
3 Blue LPM IN-
2 Red +12 VDC
1 Black GND.
Figure 5 - Interface Cable Configuration for MX421B
Where:
Pins 1 & 2: are the GND and 12 VDC power input.
Pins 3 & 4: Leica proprietary message (LPM) input port.
Pins 5 & 6: GPS output to the MK40, MX420 or other NMEA 0183 compatible
devices.
Pins 7 & 8: Beacon monitoring signal output.

13
MX421 Installation Manual
Data Interface to MK40 Chartplotter
The MX421 and MX421B connection to the MK40 antenna terminal box is shown
below. Only three wires from the MX421 or MX421B cable are used, namely;
RED ------------------+12VDC
Black/Shield-------- NegativeReturnandSignalGND
GREEN------------- GPS Data +
TxD(BRW)
N.C.(WHT)
RxD(GRN)
+12 V(RED)
GND (SHD)
C
N
1
RX
DG
TXD
GND
12V
P
i
n
6
(
G
r
e
e
n
)
G
P
S
O
U
T
P
i
n
1
(
Black/Shield)
GND
Pin2(Red)+12 VDC
MX421
MX421B
To MK40
Figure 6 - MX421 Interface to the MK40 Chartplotter

14
MX421 Installation Manual
Data Interface to a PC or Non-Leica Navigation Systems
Figure 7 shows the power and data output connections to non-Leica navigation
systemsusingaterminal strip and DB9connector(usersupplieditems)toterminate
the wires.
Pin6(Gr
e
e
n
)
G
P
S
O
U
T
Pin1(
Black/Shield) Gnd
Pin2(Red)+12 VDC
2 Amp
Fuse
1 2 6
GPS Data Out
Common GND
To Navigation
PC
Terminal
Strip
Red
Green
Black/ Shield
1
2
3
4
5
6
7
8
9
DB9 Connector
(Female)
Figure 7 - MX421 Interface to PC or other Non-Leica Navigation Systems